CCL: Applicability of Density Functional

 Sent to CCL by: "Haibin  Li" [lihb734,yahoo.com]
 Dear CCLers:
   As we know, Density Funtional Theory (DFT) become more and more popular in the
 field of Computational Chemistry. Although the exact form of
 Exchange-Correlation Functional is not known, many expert have developed a wide
 variety of approximate functional designed to specific systerms, for example,
 SAOP potential was developed specifically to investigate spectropic properties.
 Thus, when a novice enter the fied of DFT, how can he understand which
 functional is suitable for the systems under his investigation? Is there any
 reference or deposity or database to which we can refer? Or, we should read all
 papers concerning the developmen of functional, benchmark test
  Thanks in advance for your help.